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Person

Michelle L Hladik

Research Chemist

Email: mhladik@usgs.gov
Office Phone: 916-278-3183
Fax: 916-278-3070
ORCID: 0000-0002-0891-2712

Location
Placer Hall
6000 J Street
Sacramento , CA 95819-6129
US
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This data release contains the concentration and quality-assurance results for inorganic constituents, as well as organic compounds (volatile organic compounds [VOC], per- and polyfluoroalkyl substances [PFAS], pesticides and disinfection byproducts [DBP]) and microbiological results collected in the Little Big Horn River and residential or commercial tapwater locations in Montana. Twenty-two tapwater samples (six sourced from public supply and 14 sourced from private wells) and six surface-water samples were collected in Montana between August 8-10, 2022. Pharmaceuticals, VOC, and PFAS were analyzed at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) in Denver, Colorado. Pesticides and...
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Neonicotinoids have become the most widely used insecticides in world with rapid growth in applications as seed coatings. Nontarget organisms are exposed to concentrated levels of pesticidal active ingredients through ingestion of treated seeds. To better understand pesticide fate, analytical methods are necessary to rapidly screen and accurately quantitate contaminants in environmental and biological matrices. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is commonly employed for neonicotinoid analyses but requires expensive analytical instrumentation and potentially laborious sample preparation. Enzyme-linked immunosorbent assays (ELISAs) are efficient and sensitive alternative methods for neonicotinoid...
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These data present chemistry and toxicity results from freshwater stream sediments collected from 99 wadable stream sites across eleven states in the Midwestern U.S. as one component of a larger USGS study in the summer of 2013. This data presents a selected suite of chemistry collected at these sites (PAHs, Organochlorines, PCBs, Trace Elements, and current use pesticides) used in calculating a Probable Effect Concentration-Likely Effect Benchmark quotient mixture score for contaminants measured in sediments. The toxicity data presents results of toxicity tests following ASTM and US EPA standard methods for sediment toxicity tests with the amphipod Hyalella azteca (28-d exposure), the midge Chironomus dilutus (10-d),...
This data release includes sampling location data, field-collected wetland attribute data, field-collected water chemistry data, laboratory-processed water chemistry data (anions, cations, alkalinity, nutrients, chlorophyll a concentrations, dissolved organic carbon, and specific ultraviolet absorbance, pesticide concentrations), dry mass of adult aquatic insects emerging from the surface of the wetlands, taxonomic classifications of the insects collected, and whole-body pesticide concentrations for adult aquatic insects emerging from wadeable wetlands in cropland and grassland landscapes across a salinity/hydrology gradient (N = 14 wetlands in 2015, N = 15 wetlands in 2016). Sampling was completed in late spring,...
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Zooplankton samples were collected at one site upstream of the Yolo Bypass in Northern California, three sites within the Bypass, and at a comparison site on the Sacramento River below the city of Sacramento and analyzed for a large suite of current-use pesticides and degradates. Samples were collected every two weeks from early August 2021 to mid-October 2021. Samples were collected by towing a 150-micron conical plankton net for 5 minutes by boat at each site. In the laboratory, zooplankton samples were filtered through a 63-micrometer sieve to separate the zooplankton and vegetation/detritus from the water. Large sticks, twigs, rocks, and leaves were rinsed with organic free water into the sieve and then discarded....
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